session-ios/SessionMessagingKit/Utilities/DeviceSleepManager.swift

81 lines
2.4 KiB
Swift

//
// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
//
import Foundation
// This entity has responsibility for blocking the device from sleeping if
// certain behaviors (e.g. recording or playing voice messages) are in progress.
//
// Sleep blocking is keyed using "block objects" whose lifetime corresponds to
// the duration of the block. For example, sleep blocking during audio playback
// can be keyed to the audio player. This provides a measure of robustness.
// On the one hand, we can use weak references to track block objects and stop
// blocking if the block object is deallocated even if removeBlock() is not
// called. On the other hand, we will also get correct behavior to addBlock()
// being called twice with the same block object.
@objc
public class DeviceSleepManager: NSObject {
@objc
public static let sharedInstance = DeviceSleepManager()
private class SleepBlock: CustomDebugStringConvertible {
weak var blockObject: NSObject?
var debugDescription: String {
return "SleepBlock(\(String(reflecting: blockObject)))"
}
init(blockObject: NSObject) {
self.blockObject = blockObject
}
}
private var blocks: [SleepBlock] = []
private override init() {
super.init()
NotificationCenter.default.addObserver(self,
selector: #selector(didEnterBackground),
name: NSNotification.Name.OWSApplicationDidEnterBackground,
object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
@objc
private func didEnterBackground() {
ensureSleepBlocking()
}
@objc
public func addBlock(blockObject: NSObject) {
blocks.append(SleepBlock(blockObject: blockObject))
ensureSleepBlocking()
}
@objc
public func removeBlock(blockObject: NSObject) {
blocks = blocks.filter {
$0.blockObject != nil && $0.blockObject != blockObject
}
ensureSleepBlocking()
}
private func ensureSleepBlocking() {
// Cull expired blocks.
blocks = blocks.filter {
$0.blockObject != nil
}
let shouldBlock = blocks.count > 0
CurrentAppContext().ensureSleepBlocking(shouldBlock, blockingObjects: blocks)
}
}